On September 8, 1943, Italy surrendered to the Allies in WWII. From the article:
"Italian surrender is announced
On September 8, 1943, Gen. Dwight Eisenhower publicly announces the surrender of Italy to the Allies. Germany reacted with Operation Axis, the Allies with Operation Avalanche.
With Mussolini deposed from power and the earlier collapse of the fascist government in July, Gen. Pietro Badoglio, the man who had assumed power in Mussolini’s stead by request of King Victor Emanuel, began negotiating with Gen. Eisenhower for weeks. Weeks later, Badoglio finally approved a conditional surrender, allowing the Allies to land in southern Italy and begin beating the Germans back up the peninsula. Operation Avalanche, the Allied invasion of Italy, was given the go-ahead, and the next day would see Allied troops land in Salerno.
The Germans too snapped into action. Ever since Mussolini had begun to falter, Hitler had been making plans to invade Italy to keep the Allies from gaining a foothold that would situate them within easy reach of the German-occupied Balkans. On September 8, Hitler launched Operation Axis, the occupation of Italy. As German troops entered Rome, General Badoglio and the royal family fled Rome for southeastern Italy to set up a new antifascist government. Italian troops began surrendering to their former German allies; where they resisted, as had happened earlier in Greece, they were slaughtered (1,646 Italian soldiers were murdered by Germans on the Greek island of Cephalonia, and the 5,000 that finally surrendered were ultimately shot).
One of the goals of Operation Axis was to keep Italian navy vessels out of the hands of the Allies. When the Italian battleship Roma headed for an Allied-controlled port in North Africa, it was sunk by German bombers. In fact, the Roma had the dubious honor of becoming the first ship ever sunk by a radio-controlled guided missile. More than 1,500 crewmen drowned. The Germans also scrambled to move Allied POWs to labor camps in Germany in order to prevent their escape. In fact, many POWS did manage to escape before the German invasion, and several hundred volunteered to stay in Italy to fight alongside the Italian guerillas in the north.
The Italians may have surrendered, but their war was far from over."